A Unique Online Method to Infer Water-Insoluble Particle Contributions

Details

• Personal Author:
  Asa-Awuku A ; Fine PM ; Giordano M ; Polidori A ; Short D ; Zhu Y
• Description:
  Particle number, size, and composition information is important for constraining aerosol effects on air quality, climate, and health. The composition of particles, especially from vehicular sources, may contain insoluble black carbon (BC) materials that modify particle nucleating properties. In this study, we develop a method to provide quantitative and real-time information on the water-insoluble components found in near-road aerosol sources. A water-based condensation particle counter (W-CPC) and a butanol-based CPC (B-CPC) were used to measure the particle number concentration. Both instruments were coupled with a scanning mobility particle sizer (SMPS) to record the particle number and size data. Real time water-insoluble particle mass was estimated from the difference in particle number concentration between the two CPCs; theoretical water-insoluble mass was calculated from the ideal hygro- scopicity single parameter k-values. This online method was calibrated with test compounds and then applied to data collected from a field study. Ambient aerosol was sampled from a monitoring station located 15 m from the I-710 freeway in Long Beach, California. The results show that near-roadway emissions contain water-insoluble (BC and non-BC) components. Particle number and BC concentrations increase after changes in wind direction near the freeway on both weekday and weekend measurements. Particles were less hygroscopic (k approximately 0.2) before changes in wind direction from downwind to upwind of the freeway (k > 0.6). Rapid changes in water-solubility can be captured with this technique. By assuming a two-component mixture, the water-insoluble mass fractions were inferred. BC shows a positive correlation with the water-insoluble mass however its presence may not account for the entire water-insoluble mass from the near-roadway source. [Description provided by NIOSH]
• Subjects:
  Aerosols Air Pollution Occupational Health Particulate Matter Safety
• Keywords:
  Aerosol Particles Air Pollution Automotive Emissions Particle Size Particle Sizers Particulates
• ISSN:
  0278-6826
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 9
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  48
• Issue:
  7
• NIOSHTIC Number:
  nn:20055791
• Citation:
  Aerosol Sci Technol 2014 Jul; 48(7):706-714
• Contact Point Address:
  Akua Asa-Awuku, Department of Chemical and Environmental Engineering, University of California- Riverside, 900 University Avenue, Riverside, CA 92507, USA
• Email:
  akua@engr.ucr.edu
• CAS Registry Number:
  Carbon black (CAS RN 1333-86-4)
• Federal Fiscal Year:
  2014
• Performing Organization:
  University of California Los Angeles
• Peer Reviewed:
  True
• Start Date:
  20050701
• Source Full Name:
  Aerosol Science and Technology
• End Date:
  20270630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:1c0b7bafdfc16e0e2367acf6c278ebd4d9f15d1975fe76da80e663357f57d11181b5d6102abdf497bf4ccec689f0e6e253c455207115a81cae21466b1491b788
• Download URL:
  https://stacks.cdc.gov/view/cdc/213560/cdc_213560_DS1.pdf
• File Type:
  [PDF - 700.86 KB ]